Titanium dioxide nanoparticles (n-TiO2) are added to photocatalytic mortars to improve urban air quality. Their activity can be increased by dispersing and binding them on natural sepiolite surface. Workers handling photocatalytic additives can be exposed to n-TiO2. However, the release of nanoparticles to the workplace can be different if the material used is raw n-TiO2 powders or if the nanoparticles are supported on sepiolite. In this work, we compare occupational exposure to n-TiO2 for raw n-TiO2 and a hybrid additive n-TiO2/sepiolite obtained by a proprietary process. Measurements were performed in two industrial sites that process 1 ton batches of mortars, formulated with the same quantity of n-TiO2, followed by their application outdoors. Direct reading instruments were used to monitor particle number concentration and size distribution. Simultaneously, filter-based samples were collected for mass concentration and microscopy analysis. Two tasks produced a significant release of particles, the addition of fillers during the mortar formulation, in site 1, and the mixing of mortar with water for its application in the second site. For the first task, particle concentration was significantly lower when the n-TiO2/sepiolite was added compared to the raw n-TiO2. For the second task, once the mortar is fully formulated, this metric does not identify differences among the batches. Titanium mass concentration was 3–10 times lower when handling the mortar formulated with the hybrid additive. These results suggest that supporting the n-TiO2 on the sepiolite network not only increases the photocatalytic activity, but is also a safer design that reduces exposure to nanoparticles. Titanium mass concentration was 3–10 times lower when handling the mortar based on the n-TiO2/sepiolite hybrid additive. Direct reading instruments (DRIs) do not allow to compare worker exposure to n-TiO2 due to their lack of chemical selectivity. Occupational exposure to n-TiO2 was below selected reference limits. The n-TiO2/sepiolite hybrid additive improves the mortars photocatalytic activity and reduce the worker exposure to n-TiO2. Titanium mass concentration was 3–10 times lower when handling the mortar based on the n-TiO2/sepiolite hybrid additive. Direct reading instruments (DRIs) do not allow to compare worker exposure to n-TiO2 due to their lack of chemical selectivity. Occupational exposure to n-TiO2 was below selected reference limits. The n-TiO2/sepiolite hybrid additive improves the mortars photocatalytic activity and reduce the worker exposure to n-TiO2.

中文翻译：

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基于更安全 n-TiO2 添加剂的光催化砂浆工业配制和应用过程中的暴露评估

将二氧化钛纳米粒子 (n-TiO2) 添加到光催化砂浆中以改善城市空气质量。它们的活性可以通过将它们分散和结合在天然海泡石表面来增加。处理光催化添加剂的工人可能会接触到 n-TiO2。但是，如果使用的材料是未加工的 n-TiO2 粉末或纳米颗粒负载在海泡石上，则纳米颗粒向工作场所的释放可能会有所不同。在这项工作中，我们比较了原始 n-TiO2 和通过专有工艺获得的混合添加剂 n-TiO2/海泡石的职业暴露于 n-TiO2。测量是在两个工业场所进行的，这些场所处理 1 吨批次的砂浆，用相同数量的 n-TiO2 配制，然后在户外应用。使用直读仪器监测粒子数浓度和尺寸分布。同时，收集基于过滤器的样品用于质量浓度和显微镜分析。有两项任务产生了大量的颗粒释放，一是在砂浆配制过程中添加填料，在现场 1，二是砂浆与水混合，以便在第二现场施工。对于第一个任务，与原始 n-TiO2 相比，当添加 n-TiO2/海泡石时，颗粒浓度显着降低。对于第二个任务，一旦砂浆完全配制，该指标不会识别批次之间的差异。处理用混合添加剂配制的砂浆时，钛的质量浓度降低了 3-10 倍。这些结果表明，在海泡石网络上支持 n-TiO2 不仅可以提高光催化活性，而且是一种更安全的设计，可以减少与纳米颗粒的接触。在处理基于 n-TiO2/海泡石混合添加剂的砂浆时，钛的质量浓度降低了 3-10 倍。由于缺乏化学选择性，直读仪器 (DRI) 不允许比较工人接触 n-TiO2 的情况。n-TiO2 的职业暴露低于选定的参考限值。n-TiO2/海泡石混合添加剂提高了砂浆的光催化活性并减少了工人对n-TiO2的暴露。在处理基于 n-TiO2/海泡石混合添加剂的砂浆时，钛的质量浓度降低了 3-10 倍。由于缺乏化学选择性，直读仪器 (DRI) 不允许比较工人接触 n-TiO2 的情况。n-TiO2 的职业暴露低于选定的参考限值。